Excess nitrogen may not solve CO2 sink mystery New research suggests that nitrogen pollution has little effect on forest growth and is unlikely to account for why North American forests seem to be a sink for the global warming gas, C02. After treating North American and European forests for 1-3 years with fertilizer containing Nitrogen15, a stable isotope that is rare in nature, Knute Nadelhoffer, associate scientist at the Woods Hole Marine Biological Laboratory in Massachusetts, and his colleagues expected to find most of the labeled nitrogen in the trees. But only 5-25% was taken up as new wood growth, with the remainder going into the soil. The finding calls into question one of the leading explanations for the "disappearance" of 1.8 gigatons of carbon from the global budget, Nadelhoffer said. Scientists have estimated that 7.1 gigatons of carbon per year are emitted by human activities such as fossil fuel burning and deforestation, he explained. Of this amount, 3.3 gigatons remain in the atmosphere as C02, 2.0 gigatons are taken up by the ocean, and 1.8 gigatons mysteriously disappear over North America. Because fossil-fuel burning and agricultural fertilization have doubled the rate at which nitrogen is made available to forests, Nadelhoffer thought the surplus might augment forest growth. By growing at a faster rate, forest plants could incorporate the missing C02, thus accounting for the carbon sink. Not only is there absence of a fertilization effect, excess nitrogen actually leads to a decline in tree growth, said John Aber, professor at the University of New Hampshire's Complex Systems Research Center. His research has shown that excess nitrogen deposition leads to soil acidification, loss of soil nutrients, and decreased C02 uptake by trees. "This doesn't mean that there isn't a sink," Nadelhoffer said. He and Aber suggest that the mechanism behind the carbon sink could be reforestation, microbial activity, or a nonbiological process. —JANET PELLEY
Even after they are detected, it is harder to recover tarballs from the water because they are dispersed, Jacqueline Michel said. Five weeks after the first New Carissa spill and one week after the fuel that remained following the ship's unsuccessful burning was spilled a second time, the pounding surf had scattered tarballs along more than 150 miles of Oregon coasdine, according to the Oregon Department of Fish and Wildlife (ODFW). Workers cleaning up the beaches are simply waiting for the tarballs to wash ashore, Jacqueline Michel said. Once they splatter onto the beach, the workers scoop diem up with shovels or spear them with sticks. Though an
ODFW spokesperson called the damage "pretty minimal," more than 300 birds had been found dead. At that point, the shellfish appeared to have escaped harm, although workers were still wrestling with die challenge of disposing of the ship. "Because heavy oil is so difficult to clean up, our energies should be focused on prevention and restoration measures," Torgan said, noting that the Coast Guard considers recovering 10% of spilled oil a "successful response." "Prevention is a lot better bang for the buck," agreed Thomas Harrison, lieutenant commander for the Coast Guard's Office of Response. —KELLYN S. BETTS
Global talks to regulate genetically modified plants stall over potential trade impacts Talks in Cartagena, Columbia, aimed at crafting the first global treaty to regulate trade in genetically modified organisms (GMOs) failed in February. The breakdown marks the first time in 20 years that attempts to agree on a draft global environmental treaty under the auspices of the United Nations Environment Programme did not meet the negotiator's selfimposed deadline. Discussions stumbled when a coalition of six large agricultural exporters—the United States, Canada, Australia, Chile, Argentina, and Uruguay—pushed for the rejection of a treaty proposal based on its implications for international trade. The proposal, put forth as a compromise by the European Union (EU) at the last minute after 10 days of intense negotiations, was supported by more than 130 other countries. The biosafety protocol would set legally binding international rules to govern the transfer, handling, and use of live GMOs. To accomplish this, it would have required exporters of genetically modified plants, seeds, and other organisms to obtain advance approval from importers, as required under the Rotterdam Convention on the Prior Informed Consent (PIC) Procedure for Certain Hazardous Chemicals
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and Pesticides in International Trade (ES&T, Nov., 1998, p. 489A). Work on the proposed protocol, an outgrowth of the Convention on Biological Diversity agreed to at the 1992 Earth Summit in Rio de Janeiro, began in 1996. All countries agree that genetically engineered seeds intended for planting should be governed by an international pact. But a major disagreement in the negotiations was whether the crops of genetically engineered plants such as corn, wheat, and soybeans, which are intended for human or animal consumption, should be included in the treaty. Such crops compose more than 90% of the international trade in GMOs, according to Greenpeace International. Most developing country officials, some scientists, and environmental and consumer groups are concerned that GMO plants could confer their special characteristics on native plants through crosspollination to produce "super weeds," which would eventually obliterate native plant species. But the food and biotechnology industries and the major agricultural exporting countries argue that GMOs have a track record demonstrating that they are not a threat to biodiversity.
The coalition of large agricultural exporters argued that for food commodities, prior approval would generate needless red tape because commodities do not enter the environment. Developing nations and EU delegates countered that it was impossible to guarantee that seeds from commodity crops would not be planted. The EU compromise would have temporarily excluded commodities but left the issue open for future consideration. "We insisted that the talks are as much about trade as the environment," said Rafe Pomerance, U.S. deputy assistant secretary of state for the environment and development. Leading the world in the production of genetically engineered crops, U.S. agricultural exports are estimated to account for more than $50 billion dollars. Although the United States could not vote at the talks because it has not ratified the 1992 Convention on Biological Diversity, it influenced the talks by joining with other agricultural exporters who had ratified the protocol. Delegates from developing countries complained that the talks were more about "biotrade" than conservation of biodiversity, a view echoed by Veit Koester, chair of the treaty drafting committee. Koester, a Danish environmental official, said that the biosafety protocol is difficult to negotiate because it is the first attempt to create a global, legally binding instrument that directly deals with trade and the environment at the same time. Unlike the Kyoto Protocol on climate change or the current negotiations on persistent organic pollutants, where the aim is a reduction or elimination of chemicals or pollutants, the biosafety talks were designed to create a mechanism for monitoring, regulating, and assessing the risks from a rapidly growing variety of genetically engineered organisms in order to protect biodiversity. Other matters stalled the talks as well, including conflict with World Trade Organization treaties and liability issues, which are priorities for developing countries. Since genetic engineering is a
new technology, GMO risks are not covered by the insurance industry. Developing country delegates said they were concerned about which country or company would be held responsible if GMOs did cross-pollinate with native plants. The liability issues remain unresolved; the EU proposal has put off consideration for four years. Delegates agreed to suspend the talks and resume them no later than May 2000.
The lack of a treaty does not mean that there will be unrestricted trade in GMOs. The EU already has restrictions on the planting of seeds and importation of food that has been genetically altered. The treaty was primarily aimed at helping developing countries, which are richly biodiverse, but currently lack the expertise and the regulations to control biotechnology. —REBECCA RENNER
Environmentalists, water agencies seek stricter controls on ballast water discharges Frustrated by the U.S. Coast Guard's meager efforts to regulate ballast water discharges from ships, a coalition of environmental organizations and water agencies petitioned EPA in January to regulate such discharges under the Clean Water Act's National Pollutant Discharge Elimination System (NPDES). Ballast water, used to stabilize ships en route, is picked up in one or more ports and discharged in others depending on cargo levels. By unintentionally carrying waterborne plants and animals, these discharges are responsible for a major portion of the more than 200 invasive species now established in San Francisco Bay, said Andrew Cohen, an environmental scientist with the San Francisco Estuary Institute at the annual meeting of the American Association for the Advancement of Science in January. At press time, EPA was still wrestling with how best to respond to the petition. "Historically, this wasn't recognized as the kind of pollutant our programs are designed to deal with," said Dorn Carlson, an environmental scientist in the agency's Office of Wetlands, Oceans, and Watersheds. "Even with all the attention this has gotten in recent years, there still is not a lot of science that can be used to determine what it takes to reduce the risk of species invasions to an acceptably low level," he added. One ballast water stowaway, the infamous zebra mussel, led to
Zebra mussels, accidentally introduced to North America via ballast water, colonize on surfaces such as docks, boat hulls, commercial fishing nets, water intake pipes and valves, as well as native mollusks and crustaceans. (Courtesy Don Schloesser, U.S. Fish and Wildlife Service)
the creation of the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990. Under this Act, the Coast Guard began monitoring ballast discharges in the Great Lakes, where the zebra mussel infestation first occurred. Ships entering these waters from outside the United States and Canada are required to conduct what is known as a ballast water exchange in midocean. During this process, ballast tanks are either pumped out and refilled with water, or the tanks are overfilled by pumping in additional water to dilute the water inside. Political will in areas outside the Great Lakes, however, was not strong enough to usher in a national ballast program until 1996 when the National Invasive Species Act was passed, said Allegra Cangelosi, a senior policy analyst
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